A straight cylindrical wire lying along the x axis has a length of 0.500 m and a diameter of 0.200 mm. It is made of a material that obeys Ohm’s law with a resistivity of o = 4.00 x 10-8 '(m. Assume that a potential of 4.00 V is maintained at x = 0, and that V " 0 at x = 0.500 m. Find
(a) The electric field E in the wire,
(b) The resistance of the wire,
(c) The electric current in the wire, and
(d) The current density J in the wire. Express vectors in vector notation.
(e) Show that E = p J.